Ticket #7068: 7068_cron_part2.diff

C:/xampp/htdocs/wordpress_trunk/wp-includes/cron.php

@@ -71 +71 @@
         return false;
 }
 
-function spawn_cron() {
+function spawn_cron( $local_time ) {
+        global $current_blog; 
+        
+        /* 
+         * do not even start the cron if local server timer has drifted 
+         * such as due to power failure, or misconfiguration
+         */
+        $timer_accurate = check_server_timer( $local_time ); 
+        if ( !$timer_accurate )
+                return; 
+                
+        //sanity check
         $crons = _get_cron_array();
-
         if ( !is_array($crons) )
                 return;
 
         $keys = array_keys( $crons );
-        if ( array_shift( $keys ) > time() )
+        $timestamp =  $keys[0]; 
+        if ( $timestamp > $local_time )
                 return;
 
+        /*
+         * multiple processes on multiple web servers can run this code concurrently 
+         * try to make this as atomic as possible by setting doing_cron switch
+         */
+         $flag = get_option('doing_cron'); 
+         
+         // clean up potential invalid value resulted from various system chaos
+         if ( $flag != 0 ) { 
+                if ( $flag > $local_time + 10*60 || $flag < $local_time - 10*60 ) {
+                        update_option('doing_cron', 0);
+                        $flag = 0; 
+                }
+         }
+         
+         //don't run if another process is currently running it
+         if ( $flag > $local_time ) 
+                return; 
+
+         update_option( 'doing_cron', $local_time + 30 );
+         
+         //proceed to run cron
         $cron_url = get_option( 'siteurl' ) . '/wp-cron.php';
         $parts = parse_url( $cron_url );
 
@@ -94 +126 @@
                 }
         } else {
                 $port = isset($parts['port']) ? $parts['port'] : 80;
-                $argyle = @ fsockopen( $parts['host'], $port, $errno, $errstr, 0.01 );
+                $argyle = @ fsockopen( $_SERVER['SERVER_ADDR'], $port, $errno, $errstr, 0.01 );
         }
 
         if ( $argyle )
@@ -105 +137 @@
 }
 
 function wp_cron() {
+        
         // Prevent infinite loops caused by lack of wp-cron.php
         if ( strpos($_SERVER['REQUEST_URI'], '/wp-cron.php') !== false )
                 return;
@@ -117 +150 @@
         $keys = array_keys( $crons );
         if ( isset($keys[0]) && $keys[0] > time() )
                 return;
-
+        
+        $local_time = time(); 
         $schedules = wp_get_schedules();
         foreach ( $crons as $timestamp => $cronhooks ) {
-                if ( $timestamp > time() ) break;
+                if ( $timestamp > $local_time ) break;
                 foreach ( $cronhooks as $hook => $args ) {
                         if ( isset($schedules[$hook]['callback']) && !call_user_func( $schedules[$hook]['callback'] ) )
                                 continue;
-                        spawn_cron();
+                        spawn_cron( $local_time );
                         break 2;
                 }
         }
@@ -190 +224 @@
         return $new_cron;
 }
 
+// stub for checking server timer accuracy, using outside standard time sources
+function check_server_timer( $local_time ) { 
+        return true; 
+}
+
 ?>